1. Field of the Invention
The present invention relates to an air bag module for a vehicle, and more particularly to a structure for installing an air bag module on a steering wheel for a vehicle capable of maximizing space utilization of an interior of the steering wheel, improving operation performance of the air bag module by minimizing interference between parts constituting the air bag module.
2. Description of the Related Art
Generally, an air bag apparatus, which is an apparatus for protecting a passenger upon collision of a vehicle, protects safety of a driver and a passenger, working together with a seat belt.
Such air bag apparatus works in the following manner, in which: when a sensor and an ECU (Electronic Controlling Unit) detect impulse, an inflator is operated instantly. Then a compressed gas is discharged and the air bag is expanded, so that impulse with respect to a face and a chest of a driver, is possibly relieved.
Among such air bag apparatus, particularly a driver air bag is generally mounted on a central part of the steering wheel, so that a danger that a face or a chest of a driver is knocked against the steering wheel due to inertia going forward upon collision of a vehicle, may be prevented.
An U.S. Pat. No. 6,142,510 (Nov. 7, 2000) discloses in detail a structure of steering wheel on which a driver air bag is mounted. The structure thereof will be described in detail in the following.
FIG. 1a is a plan view of a structure for a steering wheel of the related art, and FIG. 1b is a cross-sectional view of a structure taken along line Axe2x80x94A of FIG. 1a. Also, FIG. 1c is an exploded, perspective view illustrating the whole construction of an air bag module in FIG. 1a. 
Referring to FIG. 1a through FIG. 1c, the steering wheel 10 roughly consists of a steering wheel main body 12, an air bag module 20 mounted within the main body 12, and an air bag cover 30 for covering the air bag module 20.
Also, the air bag module 20 includes an air bag 21, a retainer 22, an inflator 23, an inflator housing 24, and a base plate 25.
Here, the air bag 21 is fixed on an upper plane of the base plate 25 with the retainer 22 intervened, and the inflator 23 is fit into a back side of the base plate 25 with the inflator 23 accommodated in the inflator housing 24.
With the inflator 23 and inflator housing 24 fit into the base plate 25 as described above, a nut 27 is fixed to a stud bolt 26 formed on the back side of the retainer 22, so that assembling of the air bag module 20 is completed.
The air bag module 20 assembled through the foregoing procedure, with being fit into the back side of the air bag cover 30, is joined to a lateral side of the air bag cover 30 corresponding to a lateral side of the retainer 22 by means of a rivet 34 with a bracket 32 intervened.
After that, an assembly consisting of the air bag module 20 and the air bag cover 30, is mounted on a central front side of the main body 12, so that assembling of the whole steering wheel 10 is completed.
In the meantime, FIG. 2 is another embodiment of the related art, schematically showing a structure in which an air bag module is mounted within a steering wheel.
As shown in FIG. 2, an air bag module 50 consists of an air bag 52, an inflator 54 arranged on a lower portion of the air bag 52, and an inflator housing 56 for receiving the inflator 54.
Also, the steering wheel 40 consists of a rim 42 constituting an outer ring, a core 44 forming a central part, and a spoke 46 connecting the rim 42 with the core 44.
The inflator 54 has a connector 55 for electrically connecting with a controlling unit connected with an impulse detecting sensor within a vehicle, and a horn switch 58 is mounted on an upper portion of the air bag 52.
The air bag module 50 accommodated in an inside of a side wall part 62 of the air bag cover 60, is joined integrally to the air bag cover 60 by means of a rivet 72 with an inflator housing 56, the air bag cover 60, and a bracket 70 faced each other.
The air bag cover 60 has a side wall part 62 projected vertically downward a predetermined length from the back side of the air bag cover 60, for receiving the air bag module 50, and the air bag cover 60 positioned within the side wall part 62 has, in its back side, a tear line (not shown) of a predetermined shape for exploding upon expansion of the air bag 52.
One end of the bracket 70 is bent outward, for coming in plane contact with a front side of the spoke 46 as shown in FIG. 2, so that this bent portion is fixed to the spoke 46 by means of a bolt 74.
As is revealed in the foregoing construction, the air bag module of the related art is configured such that the air bag cover 60, the horn switch 58, the air bag 52, the inflator 54, and the connector 55 are sequentially assembled. As the air bag module 50 consisting of combination of a plurality of parts, should be mounted in a limited space within the steering wheel 40, the size of the air bag module 50 itself is reduced, whereby space for receiving the air bag 52 becomes insufficient and interference with surrounding parts is generated upon unfolding of the air bag 52. Resultantly, such problems cause deterioration in unfolding performance of the air bag 52.
Also, as space for operation of the horn switch 58 is narrow and interference with other parts is generated, a problem that malfunction of the horn switch 58 is generated, emerges.
Additionally, due to interference between the connector 55 connected with a lower end of the inflator 54 and an end terminal of a steering wheel shaft 80 positioned on a lower part of the connector 55, a short circuit phenomenon of the connector 55 is frequently generated, whereby the air bag 52 is not properly operated.
In order to resolve such problems, the inflator 54 within the air bag module 50 should be changed in its specification, and replaced by an inflator of small capacity. But, such measure may cause undesirable results having great effect on operation performance of the air bag module 50.
To solve the above-indicated problems, it is, therefore, an object of the present invention to provide a structure for installing an air bag module on a steering wheel for a vehicle capable of improving rigidity of the steering wheel by making change of a core shape possible while improving unfolding performance of the air bag by suppressing interference between parts within the air bag module and by installing the inflator in an interior of the rim of the steering wheel, achieving integration.
The foregoing and other objects and advantages are realized by providing a structure for installing an air bag module on a steering wheel for a vehicle including: a main body consisting of a rim constituting an outer ring, a core constituting a central part, a spoke connecting the rim with the core; an inflator mounted on the rim, one end of which is connected with a connector, and to the other end of which a nozzle for discharging a gas, is provided; an air bag for expanding, provided with the gas from the inflator; a cushion housing for receiving the air bag and is fixed to an upper plane of the core; and a pipe tube for sealing surroundings of the nozzle, and connecting the inflator with the housing; in which the inflator is installed in an interior of the rim.